AMPK inhibitor BML-275 induces neuroprotection through decreasing cyt c and AIF expression after transient brain ischemia.

Stroke is a major public health problem with an imperative need for a more effective and tolerated therapy. Neuroprotective therapy may be an effective therapeutic intervention for stroke. The morbidity and mortality of stroke-induced secondary brain injury is mainly caused by neuronal apoptosis, which can be executed in a caspase-dependent or apoptosis inducing factor (AIF)-dependent manner. As apoptosis is an energy-dependent process with a relative time delay, abnormal energy metabolism could be a significant and fundamental pathophysiological basis of stroke. To our knowledge, convincible evidences that AMPK inhibition exerts neuroprotection in cerebral ischemia injury via anti-apoptosis remain to be investigated. Accordingly, the aims of this study were to investigate the protective effects of AMPK inhibitor BML-275 on cerebral ischemic/reperfusion (I/R) injury and to elucidate the underlying mechanisms. Cerebral ischemia was induced by transient middle cerebral artery occlusion (tMCAO) in male C57BL/6 mice. The therapeutic effects of BML-275 were evaluated by infarct sizes, neurological scores and the proportion of apoptotic neurons after 24 h of reperfusion. The cell apoptosis markers cyt c and AIF were also evaluated. The results showed that intraperitoneally administration of BML-275 alleviate the cerebral infarction, neurological deficit and neuronal apoptosis induced by MCAO. BML-275 simultaneously induces anti-apoptosis and decreases the expression of cyt c and AIF. This study supports the hypothesis that anti-apoptosis is one of potential neuroprotective strategies for the treatment of stroke.

Schisandrin Restores the Amyloid ß-Induced Impairments on Mitochondrial Function, Energy Metabolism, Biogenesis, and Dynamics in Rat Primary Hippocampal Neurons.

INTRODUCTION: Schisandrin which is derived from Schisandra chinensis has shown multiple pharmacological effects on various diseases including Alzheimer's disease (AD). It is demonstrated that mitochondrial dysfunction plays an essential role in the pathogenesis of neurodegenerative disorders. OBJECTIVE: Our study aims to investigate the effects of schisandrin on mitochondrial functions and metabolisms in primary hippocampal neurons. METHODS: In our study, rat primary hippocampal neurons were isolated and treated with indicated dose of amyloid ß1-42 (Aß1-42) oligomer to establish a cell model of AD in vitro. Schisandrin (2 µg/mL) was further subjected to test its effects on mitochondrial function, energy metabolism, mitochondrial biogenesis, and dynamics in the Aß1-42 oligomer-treated neurons. RESULTS AND CONCLUSIONS: Our findings indicated that schisandrin significantly alleviated the Aß1-42 oligomer-induced loss of mitochondrial membrane potential and impaired cytochrome c oxidase activity. Additionally, the opening of mitochondrial permeability transition pore and release of cytochrome c were highly restricted with schisandrin treatment. Alterations in cell viability, ATP production, citrate synthase activity, and the expressions of glycolysis-related enzymes demonstrated the relief of defective energy metabolism in Aß-treated neurons after the treatment of schisandrin. For mitochondrial biogenesis, elevated expression of peroxisome proliferator-activated receptor γ coactivator along with promoted mitochondrial mass was found in schisandrin-treated cells. The imbalance in the cycle of fusion and fission was also remarkably restored by schisandrin. In summary, this study provides novel mechanisms for the protective effect of schisandrin on mitochondria-related functions.

A role of flavonoids in cytochrome c-cardiolipin interactions.

The processes preceding the detachment of cytochrome c (cyt c) from the inner mitochondrial membrane in intrinsic apoptosis involve peroxidation of cardiolipin (CL) catalyzed by cyt c-CL complex. In the present work, we studied the effect of 17 dietary flavonoids on the peroxidase activity of cyt c bound to liposomes. Specifically, we explored the relationship between peroxidase activity and flavonoids' (1) potential to modulate cyt c unfolding, (2) effect on the oxidation state of heme iron, (3) membrane permeability, (4) membrane binding energy, and (5) structure. The measurements revealed that flavones, flavonols, and flavanols were the strongest, while isoflavones were the weakest inhibitors of the oxidation. Flavonoids' peroxidase inhibition activity correlated positively with their potential to suppress Trp-59 fluorescence in cyt c as well as the number of OH groups. Hydrophilic flavonoids, such as catechin, having the lowest membrane permeability and the strongest binding with phosphocholine (PC) based on the quantum chemical calculations exhibited the strongest inhibition of Amplex Red (AR) peroxidation, suggesting a membrane-protective function of flavonoids at the surface. The results of the present research specify basic principles for the design of molecules that will control the catalytic oxidation of lipids in mitochondrial membranes. These principles take into account the number of hydroxyl groups and hydrophilicity of flavonoids.

Sulfiredoxin-1 protects spinal cord neurons against oxidative stress in the oxygen-glucose deprivation/reoxygenation model through the bax/cytochrome c/caspase 3 apoptosis pathway.

BACKGROUND: Spinal cord ischemia/reperfusion injury is a common clinical, pathophysiological phenomenon with complex molecular mechanisms. Currently, there are no therapeutics available to alleviate the same. This study investigates the protective effects of sulfiredoxin-1 (Srxn 1) on spinal cord neurons following exposure to oxygen-glucose deprivation/reoxygenation (OGD/R) treatment. MATERIALS AND METHODS: Primary spinal cord neurons were cultured, detected by anti-tubulin ßⅢ, and transfected with adeno-associated virus (AAV)-Srxn 1 to overexpress Srxn 1. They were identified by their morphology and CCK-8 assay. The superoxide dismutase level was measured by superoxide dismutase assay. Malondialdehyde level was measured by malondialdehyde assay. The apoptosis ratio was calculated by Hoechst 33342 and Annexin V-PE/7-AAD staining. Mitochondrial transmembrane potential (Δψm) was detected by tetramethylrhodamine-methyl ester-perchlorate (TMRM) staining. The mRNA expression levels of Srxn 1 and caspase 3 were detected by quantitative reverse transcription-polymerase chain reaction, and the protein expression levels of Srxn 1, bax, bcl-2, cytosolic cytochrome c, and caspase 3 were detected by western blotting. RESULTS: AAV-Srxn 1 up-regulated mRNA and protein levels of Srxn 1 in spinal cord neurons. Following exposure to OGD/R, overexpression of Srxn 1 improved the neuronal viability, alleviated the neuron apoptosis, enhanced the mitochondrial transmembrane potential, increased the SOD level, decreased the MDA level, inhibited the expression of cytosolic cytochrome c, bax, and caspase 3, and promoted the expression of bcl-2. CONCLUSION: Srxn 1 plays a significant role in anti-apoptosis of spinal cord neurons, and Srxn 1 may be a potential therapeutic target for spinal cord I/R injury.

Phyto-chlorophyllin Prevents Food Additive Induced Genotoxicity and Mitochondrial Dysfunction via Cytochrome c Mediated Pathway in Mice Model.

OBJECTIVES: The issue of food-additive-toxicity causing several health hazards needs to be therapeutically managed with an immediate effect. Alloxan, a food additive, is used for whitening and shining flour. It is capable of inducing genotoxicity, diabetes, and associated mitochondrial dysfunction. Therefore, to explore a non-toxic, phyto-based compound that can delay the onset of diabetes and prevent the multitude of damage associated, Chlorophyllin (CHL) was selected for our study, having been reported to exhibit anti-cancer, anti-diabetes, and antiinflammatory responses. Therefore, the objective of the present study is to evaluate the protective role of CHL in controlling genotoxicity, glucose imbalance, and associated cytochrome c mediated mitochondrial signaling dysfunction against food-additive-induced genotoxicity, diabetic state, and its complexities in mice model in vivo. METHODS: Mice were pre-treated with CHL through oral gavage before they were exposed to alloxan. Diabetic markers, anti-oxidant enzyme profile, chromosomal study, mitochondrial functioning factors, and expression of proteins were checked against food-additive injected mice. RESULTS: The results revealed that CHL pre-treatment could delay the onset of diabetes, restrict alloxan-induced elevation of blood glucose, reduce DNA-damage and chromosomal aberration, optimize enzymatic profile (glucokinase, pyruvate, insulin), and modulates protein expression (insulin, IRS1, IRS2, GLUT2). Further, CHL-pre-treatment could stabilize mitochondrial-membrane-potential, intracellular calcium ion, ATP/ADP ratio, ATPase activity, thereby maintaining optimum functioning of cytochrome-c, bcl2, and caspase3 mitochondrial protein. CONCLUSION: Therefore, the present study reports, for the first time, the screening of phytobased bioactive CHL for preventing/limiting the extent of food-additive-induced genotoxicity and mitochondrial dysfunction and serves as an advanced therapeutic tool in the management of diabetes.

Oxidative/Nitrative Mechanism of Molsidomine Mitotoxicity Assayed by the Cytochrome c Reaction with SIN-1 in Models of Biological Membranes.

Molsidomine is currently used as a vasodilator drug for the treatment of myocardial ischemic syndrome and congestive heart failure, although still presenting some mitochondrial-targeted side effects in many human cells. As a model of molsidomine mitotoxicity, the reaction of cytochrome c with phosphatidylserine (PS)- and cardiolipin (CL)-containing liposomes was investigated in oxidative/nitrosative conditions imposed by SIN-1 decomposition, which renders peroxynitrite (ONOO-) as a main reactive product. In these conditions, the production of thiobarbituric acid-reactive substance (TBARs) and LOOH was affected by the lipid composition and the oxidative/nitrative conditions used. The oxidative/nitrative conditions were the exposure of lipids to SIN-1 decomposition, native cytochrome c after previous exposure to SIN-1, concomitantly to SIN-1 and native cytochrome c, native cytochrome c, and cytochrome c modified by SIN-1 that presents a less-rhombic heme iron (L-R cytc). TBARs and LOOH production by lipids and cytochrome c exposed concomitantly to SIN-1 differed from that obtained using L-R cytc and featured similar effects of SIN-1 alone. This result suggests that lipids rather than cytochrome c are the main targets for oxidation and nitration during SIN-1 decomposition. PS- and CL-containing liposomes challenged by SIN-1 were analyzed by Fourier transform infrared spectroscopy that revealed oxidation, trans-isomerization, and nitration. These products are consistent with reaction routes involving lipids and NOx formed via peroxynitrite or direct reaction of NO• with molecular oxygen that attacks LOOH and leads to the formation of substances that are not reactive with thiobarbituric acid.

Fucoidan Induces Apoptosis of HT-29 Cells via the Activation of DR4 and Mitochondrial Pathway.

Fucoidan has a variety of pharmacological activities, but the understanding of the mechanism of fucoidan-induced apoptosis of colorectal cancer cells remains limited. The results of the present study demonstrated that the JNK signaling pathway is involved in the activation of apoptosis in colorectal cancer-derived HT-29 cells, and fucoidan induces apoptosis by activation of the DR4 at the transcriptional and protein levels. The survival rate of HT-29 cells was approximately 40% in the presence of 800 µg/mL of fucoidan, but was increased to 70% after DR4 was silenced by siRNA. Additionally, fucoidan has been shown to reduce the mitochondrial membrane potential and destroy the integrity of mitochondrial membrane. In the presence of an inhibitor of cytochrome C inhibitor and DR4 siRNA or the presence of cytochrome C inhibitor only, the cell survival rate was significantly higher than when cells were treated with DR4 siRNA only. These data indicate that both the DR4 and the mitochondrial pathways contribute to fucoidan-induced apoptosis of HT-29 cells, and the extrinsic pathway is upstream of the intrinsic pathway. In conclusion, the current work identified the mechanism of fucoidan-induced apoptosis and provided a novel theoretical basis for the future development of clinical applications of fucoidan as a drug.

Taurine prevents cardiomyocyte apoptosis by inhibiting the calpain-1/cytochrome c pathway during RVH in broilers.

The calpain-1-activated apoptotic pathway plays a key role in right ventricular hypertrophy (RVH). Taurine has been shown to attenuate apoptosis by inhibiting calpain activity. This experiment aimed to determine whether taurine could prevent RVH by inhibiting the calpain-1/cytochrome c apoptotic pathway. The broilers were given 1% taurine dissolved in drinking water and were raised at 10 °C ~ 12 °C from day 21 to day 42. At 21 d, 28 d, 35 d and 42 d, the right ventricular (RV) tissues were collected. Increased RVH index, angiotensin II, norepinephrine and atrial natriuretic peptide mRNA expression were reduced by taurine in the broiler RVs. Taurine obviously inhibited cardiomyocyte apoptosis via maintaining the mitochondrial membrane potential and decreased the activation of caspase-9 and caspase-3 in the broiler RVs. The antioxidant assay demonstrated that taurine enhanced the activities of superoxide dismutase, total antioxidant capacity and glutathione peroxidase and the glutathione/glutathione disulfide ratio. Western blot results revealed that taurine also downregulated the expression of calpain-1 and cytosolic cytochrome c while upregulating the expression of Bcl-2/Bax and mitochondrial cytochrome c in broiler cardiomyocytes during RVH. In summary, we found that taurine could enhance cardiomyocyte antioxidant ability and further prevented cardiomyocyte apoptosis by inhibiting the calpain-1/cytochrome c pathway during RVH in broilers.

Exploring Mitochondria-Mediated Intrinsic Apoptosis by New Phytochemical Entities: An Explicit Observation of Cytochrome c Dynamics on Lung and Melanoma Cancer Cells.

Hydnocarpin (Hy) is a flavonoid isolated and purified from the seeds of Hydnocarpus wightiana Blume. Herein, we have developed a built-in semi-synthetic modification on Hy by one-pot multi-component reaction and a [3 + 2] cycloaddition strategy to append five membered isoxazole and isoxazolone as new phytochemical entities (NPCEs). Two selected NPCEs viz Hy-ISO-VIII and Hy-ISO-G from the library of 20 newly synthesized derivatives after in vitro screening unveiled promising cytotoxicity and induced caspase-mediated apoptosis against the human lung and melanoma cancer cells which were well supported by virtual screening based on ligand binding affinity and molecular dynamic simulations. As a new insight, we introduced surface-enhanced Raman spectroscopy to identify the chemo-marker molecular fingerprint to confirm the cellular uptake, cytochrome c release, and DNA fragmentation in a label-free manner. The present findings throw up a surfeit of seminal reasons behind the semi-synthetic modification of Hy, stepping forward to cancer chemotherapy.

High PGAM5 expression induces chemoresistance by enhancing Bcl-xL-mediated anti-apoptotic signaling and predicts poor prognosis in hepatocellular carcinoma patients.

Hepatocellular carcinoma (HCC) is the one of most common and deadly cancers, and is also highly resistant to conventional chemotherapy treatments. Mitochondrial phosphoglycerate mutase/protein phosphatase (PGAM5) regulates mitochondrial homeostasis and cell death, however, little is known about its roles in cancer. The aim of this study was to explore the clinical significance and potential biological functions of PGAM5 in hepatocellular carcinoma. For the first time, our results show that PGAM5 is significantly upregulated in HCC compared with corresponding adjacent noncancerous hepatic tissues and high PGAM5 expression is an independent predictor of reduced survival times in both univariate and multivariate analyses. Additionally, in vivo and in vitro studies showed that depleting PGAM5 expression inhibited tumor growth and increased the 5-fluorouracil sensitivity of HCC cells. Conversely, restoring PGAM5 expression in PGAM5-knockdown cells dramatically enhanced HCC cell resistance to 5-fluorouracil. Importantly, we demonstrated that the mechanism of 5-fluorouracil resistance conferred to HCC cells by PGAM5 was via inhibiting BAX- and cytochrome C-mediated apoptotic signaling by interacting and stabilizing Bcl-xL. Consistently, in the same cohorts of HCC patient tissues, Bcl-xL expression was positively correlated with PGAM5, and together predicted poor prognoses. In Conclusion, Our data highlight the molecular etiology and clinical significance of PGAM5 in HCC. Targeting the novel signaling pathway mediated by PGAM5/Bcl-xL may represent a new therapeutic strategy to improve the survival outcomes of HCC patients.

Effect of Src Kinase inhibition on Cytochrome c, Smac/DIABLO and Apoptosis Inducing Factor (AIF) Following Cerebral Hypoxia-Ischemia in Newborn Piglets.

We have previously shown that cerebral Hypoxia-ischemia (HI) results in activation of Src kinase in the newborn piglet brain. We investigated the regulatory mechanism by which the pre-apoptotic proteins translocate from mitochondria to the cytosol during HI through the Src kinase. Newborn piglets were divided into 3 groups (n = 5/group): normoxic (Nx), HI and HI pre-treated with Src kinase inhibitor PP2 (PP2 + HI). Brain tissue HI was verified by neuropathological analysis and by Adenosine Triphosphate (ATP) and Phosphocreatine (PCr) levels. We used western blots, immunohistochemistry, H&E and biochemical enzyme assays to determine the role of Src kinase on mitochondrial membrane apoptotic protein trafficking. HI resulted in decreased ATP and PCr levels, neuropathological changes and increased levels of cytochrome c, Smac/DIABLO and AIF in the cytosol while their levels were decreased in mitochondria compared to Nx. PP2 decreased the cytosolic levels of pre-apoptotic proteins, attenuated the neuropathological changes and apoptosis and decreased the HI-induced increased activity of caspase-3. Our data suggest that Src kinase may represent a potential target that could interrupt the enzymatic activation of the caspase dependent cell death pathway.

Cerebrovascular Protective Effect of Boldine Against Neural Apoptosis via Inhibition of Mitochondrial Bax Translocation and Cytochrome C Release.

BACKGROUND In the present study, we explored the protective effect and mechanism of action of boldine (BOL) against neural apoptosis, which is a mediator of TBI. MATERIAL AND METHODS The effect of BOL on mitochondrial and cytosol proteins of extracted from cerebral cortical tissue of mice was evaluated. The grip test was used to assess the neurological deficit and brain water content of the subjects after administration of BOL to assess its effect on SOD, GSH, and MDA activity in brain ischemic tissues. To further confirm the effect of the BOL, the histopathological analysis and morphology of neurons were studied by Nissl staining. The effect of BOL against TBI-induced neural apoptosis by immuno-histochemistry and Western blotting assay were also studied. RESULTS BOL showed significant improvement against TBI in a dose-dependent manner. In the BOL-treated group, the apoptotic index was significantly reduced, but the level of caspase-3 was greatly diminished. Additionally, the level of the Bax in mitochondria (mit) and cytosol was elevated in the TBI-treated group as compared to the sham group. Further BOL at the test dose causes significant reduction in the level of mitochondrial MDA together with increase in SOD activity as compared to the TBI alone group. CONCLUSIONS BOL showed a cerebroprotective effect against TBI by attenuating the oxidative stress and the mitochondrial apoptotic pathway. It also inhibited mitochondrial Bax translocation and cytochrome c release.

P7C3 inhibits GSK3ß activation to protect dopaminergic neurons against neurotoxin-induced cell death in vitro and in vivo.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease. Although its pathogenesis remains unclear, mitochondrial dysfunction plays a vital role in the pathology of PD. P7C3, an aminopropyl carbazole, possesses a significant neuroprotective ability in several neurodegenerative disorders, including PD. Here, we showed that P7C3 stabilized mitochondrial membrane potential, reduced reactive oxygen species production, and inhibited cytochrome c release in MES23.5 cells (a dopaminergic (DA) cell line) exposed to 1-methyl-4-phenylpyridinium (MPP+). In MES23.5 cells, P7C3 inhibited glycogen synthase kinase-3 beta (GSK3ß) activation induced by MPP+. P7C3 also inhibited p53 activity and repressed Bax upregulation to protect cells from MPP+ toxicity. In addition, the activation of p53 was significantly attenuated with the inhibition of GSK3ß activity by P7C3. Furthermore, P7C3 blocked GSK3ß and p53 activation in the midbrain, and prevented DA neuronal loss in the substantia nigra in 1-methyl-4-phenyl-1,2,3,4-tetrahydropyridine mice. Thus, our study demonstrates that P7C3 protects DA neurons from neurotoxin-induced cell death by repressing the GSK3ß-p53-Bax pathway both in vitro and in vivo, thus providing a theoretical basis for P7C3 in the potential clinical treatment of PD.

ß-lactam Structured, 4-(4-(Methylsulfonyl)phenyl)-1-pentyl-3-phenoxyazetidin-2-one: Selectively Targets Cancerous B Lymphocyte Mitochondria.

BACKGROUND: ß lactam-structured Cox-2 inhibitors, possesses anti-proliferative and anti-inflammatory effects. OBJECTIVE: In this research, the actions of a synthetic ß lactam-structured Cox-2 inhibitor with 4-(4- (Methylsulfonyl) phenyl)-1-pentyl-3-phenoxyazetidin-2-one on cellular viability of cancerous lymphoblast obtained from patients with acute lymphocytic leukemia (ALL) and normal lymphocytes obtained from healthy donors were compared. METHODS: % the cell viability of cancerouslymphoblasts and normal lymphocytes treated with ß lactam derivatives were assayed with MTT test. Early apoptosis and necrosis were detected by double staining of annexin V/ propidium iodide and activity of caspase 3 as the final mediator in apoptotic mode of cell death was evaluated by colorimetric assay. RESULTS: Our results showed that ß lactam derivatives inhibited the proliferation of cancerous lymphoblast but not normal lymphocytes in a concentration-dependent mode by inducing apoptosis. Treatment with ß lactam derivatives resulted in a rapid loss of mitochondrial trans-membrane potential and induction of reactive oxygen species (ROS) formation, and cytochrome c release in cytosol of mitochondria resulted in activation of procaspase-9 and formation of active apoptosome. CONCLUSION: These findings suggest that 4-(4-(Methylsulfonyl)phenyl)-1-pentyl-3-phenoxyazetidin-2-one as a ß lactam could induce ROS-mediated death signaling throughmitochondrial pathway that results in apoptosis in only cancerous lymphoblast cells. The stimulationof apoptosis by ß lactams may provide a pivotal mechanismfor their anticancer effect in acute lymphocytic leukemia cells.

Calcium-sensing receptor antagonist NPS2390 attenuates neuronal apoptosis though intrinsic pathway following traumatic brain injury in rats.

Traumatic brain injury (TBI) initiates a complex cascade of neurochemical and signaling changes that leads to neuronal apoptosis, which contributes to poor outcomes for patients with TBI. Previous study indicates that calcium-sensing receptor (CaSR) activation contributes to neuron death in focal cerebral ischemia-reperfusion mice, however, its role in neuronal apoptosis after TBI is not well-established. Using a controlled cortical impact model in rats, the present study was designed to determine the effect of CaSR inhibitor NPS2390 upon neuronal apoptosis after TBI. Rats were randomly distributed into three groups undergoing the sham surgery or TBI procedure, and NPS2390 (1.5 mg/kg) was infused subcutaneously at 30 min and 120 min after TBI. All rats were sacrificed at 24 h after TBI. Our data indicated that NPS2390 significantly reduced the brain edema and improved the neurological function after TBI. In addition, NPS2390 decreased caspase-3 levels and the number of apoptotic neurons. Furthermore, NPS2390 up-regulated anti-apoptotic protein Bcl-2 expression and down-regulated pro-apoptotic protein Bax, and reduced subsequent release of cytochrome c into the cytosol. In summary, this study indicated that inhibition of CaSR by NPS2390 attenuates neuronal apoptosis after TBI, in part, through modulating intrinsic apoptotic pathway.

2',3'-Cyclic nucleotide 3'-phosphodiesterase as a messenger of protection of the mitochondrial function during melatonin treatment in aging.

The process of aging is considered to be tightly related to mitochondrial dysfunction. One of the causes of aging is an increased sensitivity to the induction of mitochondrial permeability transition pore (mPTP) opening in the inner membrane of mitochondria. Melatonin, a natural antioxidant, is a hormone produced by the pineal gland. The role of melatonin whose level decreases with aging is well understood. In the present study, we demonstrated that long-term treatment of aged rats with melatonin improved the functional state of mitochondria; thus, the Ca2+ capacity was enhanced and mitochondrial swelling was deaccelerated in mitochondria. Melatonin prevented mPTP and impaired the release of cytochrome c and 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) from mitochondria of both young and aged rats. Our data suggest that melatonin retains СNPase inside mitochondria, thereby providing the protection of the protein against deleterious effects of 2',3'-cAMP in aging.

Protein Surface Mimetics: Understanding How Ruthenium Tris(Bipyridines) Interact with Proteins.

Protein surface mimetics achieve high-affinity binding by exploiting a scaffold to project binding groups over a large area of solvent-exposed protein surface to make multiple cooperative noncovalent interactions. Such recognition is a prerequisite for competitive/orthosteric inhibition of protein-protein interactions (PPIs). This paper describes biophysical and structural studies on ruthenium(II) tris(bipyridine) surface mimetics that recognize cytochrome (cyt) c and inhibit the cyt c/cyt c peroxidase (CCP) PPI. Binding is electrostatically driven, with enhanced affinity achieved through enthalpic contributions thought to arise from the ability of the surface mimetics to make a greater number of noncovalent interactions than CCP with surface-exposed basic residues on cyt c. High-field natural abundance 1 H,15 N HSQC NMR experiments are consistent with surface mimetics binding to cyt c in similar manner to CCP. This provides a framework for understanding recognition of proteins by supramolecular receptors and informing the design of ligands superior to the protein partners upon which they are inspired.

Amelioration of apoptotic events in the skeletal muscle of intra-nigrally rotenone-infused Parkinsonian rats by Morinda citrifolia--up-regulation of Bcl-2 and blockage of cytochrome c release.

Parkinson's disease is a progressive neurodegenerative movement disorder with the cardinal symptoms of bradykinesia, resting tremor, rigidity, and postural instability, which lead to abnormal movements and lack of activity, which in turn cause muscular damage. Even though studies have been carried out to elucidate the causative factors that lead to muscular damage in Parkinson's disease, apoptotic events that occur in the skeletal muscle and a therapeutical approach to culminate the muscular damage have not been extensively studied. Thus, this study evaluates the impact of rotenone-induced SNPc lesions on skeletal muscle apoptosis and the efficacy of an ethyl acetate extract of Morinda citrifolia in safeguarding the myocytes. Biochemical assays along with apoptotic markers studied by immunoblot and reverse transcription-polymerase chain reaction in the current study revealed that the supplementation of Morinda citrifolia significantly reverted alterations in both biochemical and histological parameters in rotenone-infused PD rats. Treatment with Morinda citrifolia also reduced the expression of pro-apoptotic proteins Bax, caspase-3 and caspase-9 and blocked the release of cytochrome c from mitochondria induced by rotenone. In addition, it augmented the expression of Bcl2 both transcriptionally and translationally. Thus, this preliminary study paves a way to show that the antioxidant and anti-apoptotic activities of Morinda citrifolia can be exploited to alleviate skeletal muscle damage induced by Parkinsonism.

The effect of amixin and agmatine on cytochrome C release from isolated mitochondria

Mitochondrial nicotinic acetylcholine receptors (nAChRs) control permeability transition pore formation and cytochrome c release in the presence of apoptogenic factors. This study demonstrates that pharmacological agents amixin and agmatine affect mitochondrial nAChR functioning: they slightly suppress cytochrome c release from mouse brain and liver mitochondria stimulated with apoptogenic dose of Са2+ and prevent the effect of α7 nAChR agonist PNU282987. We conclude that mitochondria may be one of therapeutic targets of amixin and agmatine.

[Peculiarities of the Structural-Functional State of the Cytochrome Part of Liver Mitochondrial Respiratory Chain under Conditions of Acetaminophen-induced Hepatitis against the Background of Alimentary Deprivation of Protein].

Activity of the key enzyme of the cytochrome part of the respiratory chain--cytochrome oxidase, quantitative redistribution of mitochondrial cytochromes b, c1, c and aa3, activity of the key enzymes of cytochromes' heme metabolism--delta-aminolevulinate synthase and heme oxygenase under conditions of acetaminophen-induced hepatitis against the background of alimentary deprivation of protein were studied. It was found out, that under conditions of acetaminophen-induced hepatitis against the background of alimentary deprivation of protein, an inhibition of cytochrome oxidase activity and a decrease in the quantitative content of mitochondrial cytochromes against the background of the increase in the delta-aminolevulinate synthase and heme oxygenase activity are observed. In animals with toxic liver injury, maintained under conditions of alimentary deprivation of protein, a progressive decrease in the quantitative content of mitochondrial cytochromes b, c1, c and aa3 against the background. of the increase in heme oxygenase activity and preservation of delta-aminolevulinate synthase activity on the control level is identified. The conclusion was made, that alimentary deprivation of protein is a critical factor for the development of the disturbances of structural-functional integrity of the cytochromic part of the respiratory chain. The identified changes may be considered as one of the possible mechanisms of energy biotransformation system disturbances under conditions of alimentary deprivation of protein.